The present invention relates generally to laundry machines. More particularly, the present invention relates to an improved washer/dryer combination for use in the washing and drying of clothes, bed sheets, towels and other articles.
As is well known, a washing machine is an appliance for separating dirt from articles to be washed, such as clothing, by sequentially carrying out various operations such as liquid feeding, washing, rinsing, dehydrating, and draining cycles. Generally, the washing machine has an outer tub for receiving a washing liquid and a spin tub accommodated in the outer tub for holding the articles to be washed.
While the washing cycle is being executed, a pulsator, which is driven by a motor, generates a swirling liquid in the spin tub, so the articles which are placed in the spin tub are washed by means of the swirling liquid.
In addition, while the dehydrating cycle is being executed, the motor rotates the spin tub, so the articles are forced toward a side wall of the spin tub due to a centrifugal force. Accordingly, the washing liquid contained in the articles is drained out of the washing machine through discharging holes which are formed in the side wall of the spin tub.
Recently, washing machines have been designed which not only wash the articles but can also dry them. These kinds of washing machines, which are called washing/drying machines, are advantageous for a number of reasons. They can reduce drying time and do not require a separate location for drying the articles. These machines save time and effort for the user. Clothing and other articles do not need to be washed in one machine then removed and loaded into a separate machine for drying. Perhaps just as importantly, a combination washer/dryer is advantageous from the standpoint of a laundromat since each machine can perform either function thus allowing more machines to be in use at one time.
Several washer/dryer combination designs are known. One such device is shown in U.S. Pat. No. 5,718,130. This device is a washing/drying machine which employs a top-loading spin tub rotating around a vertical axis. A blower is mounted on the base portion of the spin tub and blows heated air upwardly so as to direct the heated air toward the side wall of spin tub and onto articles placed in the spin tub.
A disadvantage of this device is that it does not employ a hot air outlet in the door which would allow hot air to be blown directly on the articles for drying. Another disadvantage of this device is that it is not a front-loading machine, thus, reducing its capacity.
Another known device is shown in U.S. Pat. No. 5,121,615. This device is a front-loading combination washer/dryer which includes a housing with a perforated drum disposed in the housing to ensure that all the hot air enters the rotatable drum. The device provides a drying device to be used in conjunction with a washing machine. A stationary drum positioned around the rotatable drum prevents hot air from escaping from the housing of the drying device without entering the rotatable drum so as to dry clothes. A plurality of circumferentially spaced ribs extend from the outer surface of the perforated wall toward the stationary drum, dividing the clearance between the two drums into several isolated chambers.
A disadvantage of this device is that it needs additional components to ensure that all of the hot air enters the drying chamber. Another disadvantage of this machine is that the door is not employed as either a hot air inlet or an exhaust outlet.
Still another known device is shown in U.S. Pat. No. 5,111,673. This device is a washing-drying machine which has a tub mounted in a prism-shaped housing by a pair of tilting shafts in order to carry out the washing-rinsing-spinning steps while the tub is in a substantially vertical orientation and to carry out the warm-air drying step with the tub in a substantially horizontal orientation. The tilting shafts are arranged on a horizontal axis extending through diagonally opposite corners of the housing so that the capacity of the tub can be maximized, even though the tub tilts.
A disadvantage of this device is that it requires tilting of the tub from a vertical axis for washing to a horizontal axis for drying. This construction obviously adds to the complexity of the machine, and hence, its cost.
Yet another known device is shown in the U.S. Pat. No. 5,074,131. The device is a washing/drying machine capable of effecting washing and drying as a continuous process. Washing, rinsing, dehydrating and drying are performed while a rotary basket is retained in a vertical position. After the dehydration, the rotary basket is inclined and is rotated on its axis, so that an opening end of the rotary basket is located slightly higher than the horizontal. In this state, hot air for drying is blown into the rotary basket from the opening side.
A disadvantage of this device is that it requires tilting of the rotary basket axis to switch the machine from the washing phase to the drying phase. Such tilting would not be necessary if the machine were simply a front-loading washer employing a basket which rotates on a horizontal axis.
A further known device is shown in U.S. Pat. No. 5,029,458. This device is a washing and drying machine which has a drum mounted in an outer tank for rotation about a substantially horizontal axis and a reversible motor operable at a fixed speed for driving the drum. During washing and drying operations, the direction of rotation of an output shaft of the motor is switched in short periods while a speed-changing device transmits the rotation of the output shaft of the motor to the drum axle at a reduced speed. During dehydration, the motor operates unidirectionally and the speed-changing device transmits the unidirectional rotation of the motor output shaft to the drum axle with a speed reduction in an initial stage of the dehydration operation and, thereafter, without speed reduction.
A disadvantage of this device is that it is complex and requires the changing of the speed of the output shaft of a motor between dehydration and drying stages. The machine is also a top loader, limiting its capacity.
A still further known device is shown in U.S. Pat. No. 4,757,699. This device is a washing machine which includes a wash tub, a basket for receiving laundry and mounted for rotation within the wash tub, and heater elements which are located within the chamber to thereby heat the washing liquid discharged into the chamber. The device further includes an air drying circuit whereby air is recirculated through an air duct by means of a fan from the bottom of the wash tub to the chamber. The recirculated air is heated by the heating elements.
While this machine appears to have a tub rotating around a horizontal axis, there does not appear to be any mention of the door of the machine. Certainly, there is no mention of employing an aperture in the door either for blowing hot air on the articles or for venting exhaust air from the machine.
Another known device is shown in U.S. Pat. No. 4,270,281. This device is a washing and drying machine having a perforated drum rotatable with a liquid container having, in its upper portion, a recess in which is disposed a heat-register or heating element and a reflector providing for direct irradiation of the drum.
A disadvantage of this device appears to be that it requires the heating element to be disposed within the drum, thus exposing the heating element to detergent in the washing liquid, possibly comprising its longevity.
Accordingly, it has been considered desirable to develop a new and improved washer/dryer combination which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.